Magnetic ore-separator.



PATENTED OCT. 9, 1906.

H. H. WAIT.

MAGNETIG ORB SEPARATOR'.

APPLICATION FILED MAR. 20, 1905.

2 SHEETSSEEET l.

wiaeskseay No. 8323-826. PAVTEHTED OCT. 9, 1906.

H. H. WAIT.

MAGNETIC ORE SBPZARATOR.

APPLICATION FILED MAR- 20, 1905- v BEETS-sum 2.

UNITED s'r rns PATENT OFFICE.

HENRY H. WAIT, OF CHICAGO, lLLINOIS, ASSIGNOR TO INTERNATIONAL SEPARATORCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW JERSEY.

MAGNETIC OREHSEPARATOR.

Specification of Letters Patent.

Patented Oct. 9, 1906.

Application filed Maren 20,1905. Serial No. 251,073.

rator, and has for its object to provide a machine which will beespecially effective for g the separation of ores of very low magneticpermeability, which separation requires the action of an extremelyintense and concentrated magnetic field.

In magnetic attraction the movement of the permeable particle is alwaysin the direction of converging lines of force-that is to say, themovement is toward the densest portion of the magnetic field. Inaccordance with my invention an extremely dense and concentrated fieldis formed by constructing the opposing magnetic pole-pieces betweenwhich the separating-field is established in the general form of twowedges facing each other at an angle, preferably at right angles, andthe material to be separated is passed between these opposing magneticcrosswedges, so that the more permeable particles are attracted to thesurface of one of them, which therefore is made movable in order thatthe attracted material may be removed at a point distant from the placeof separation.

A further feature of myinvention consists of the provision ofelectromagnetic coils so placed as to oppose the assage-of lines offorce in certain paths to irect these lines of force into other pathsfrom which they would otherwise tend to stray, the object being toproduce a more concentrated magnetic field than would otherwise bepossible.

My invention will be more particularly described and further featuresthereof pointed out in connection with the accompanying drawings, whichillustrate a magnetic separator embodying said invention.

Figure 1 is a vertical sectional elevation of the ore-separator. Fig. 2is a plan view thereof, the trough for feeding the ore being omitted forclearness and the auxiliary magnet-coi ls being shown in section. Fig. 3is a ridgethat is tureaxis.

diagram of curves, illustrating the intensities of the magnetic field atdifferent points and also illustrating in a dotted curve a variation inthe distribution of the flux to producea larger field of a commondensity at the particular place desired, as may be accomplished by theuse of the auxiliary magnetizing-coils, hereinafter to be described.Fig. 4 is a detail sectional view on line 4 4 of Fig. 1, showing therelation of the auxiliary magnetizingcoils to the armature or revolvingseparatingcarrier. Figs. 5, 6, and 7 are diagrams illustrating differentforms of pole-pieces and the distribution of the magnetic flux securedin each case.

The same letters of-reference indicate, the same parts wherever they areshown,

Referring first to Figs. 1 and 2, the magnetic separator consists of ama net-frame, preferably of hollow box form, wit inwardlyprojectingpole-pieces N and S and suitable magnetizingwindings therefor, creatinga magnetic flux from one to the other-that is tosay, the pole-piecesbeing of opposite polarity. Between the pole-pieces the armature B isrotatably mounted, the journals of the armature-shaft being at neutralpoints in the sides of the magnet-frame. The ore or material to beseparated is arranged to be fed by means of a chute D between the faceof the armature B and one of the poleieces N. In accordance with myinvention t e armature B and pole-piece N are formed so as to presentridges facing each other and extend-' ing in lines at an angle to eachother. More particularly describing the machine illustrated, the end ofthe pole-piece N is beveled above and below, so that it is formed like awedge, with its edge in a horizontal plane facing the armature B. Thearmature B, on the other hand, is beveled upon its two sides, so that asection of its edge oppositethe polepiece N would also be in the form ofa wedge. Thus we have the armature formed with a circumferential ridgefacing a pole-piece, the end of which is formed to present a ridge atright an les with the plane of the armatureto say, parallel with thearma- By this means it will be seen that the magnetic flux between thepolcpiecc N and the arn'laturc B will be highly concentrated upon theprojecting circnnifcrential edge of said armature at the point oppositethe pole-piece N. The direction of the magnetic lines of force willtherefore be widely divergent from the extremity of the peripheralarmature-ridge toward the opposing edge of the wedge-shaped pole-piece Nat right angles. The feed-chute D is arranged to direct the material tobe separated into the space between the circumferential ridge or edge ofthe armature and the opposing edge of the magnet-polethat is, intothedensest portion of the magnetic field. The edge of the pole-piece ispreferably provided with a non-magnetic shield E to prevent theparticles. of material being treated from coming into a position wherethe influence of the pole-piece N is stronger than that of the armature13.. F and G are divider-plates for separating the magneticmateriahwhich tends to. fall straight down away from said armature.

In. order to concentrate the lines of force more effectually in theseparating-gap. between the armature and the ole-piece N, I preferablyprovide the a 'ary countermagnetizing coilsA A at the end of the pole-.piece N and at either side thereof. The magnetiz' current sent throughthese coils should e in. the direction toproducemagnetic fluxessurrounding said coils in such a direction as to. assist the fluxbetween the poles piece N and the armature B, where said pole piece and:armature most closely approach that is,,at the separating-gapwhileopposing theleakage-tlux from theextreme edgesot said pole-piece Ntoward the armature. In other Words, the Location and magnetization ofthe auxiliary coils should be such asv to, prevent lines of force fromstraying from the outer edges. of the pole-piece toward the armature andto direct such lines of force through the portion of the pole-piecewhich is directly 0 posite the edge of the separati -armature. '1 hisfeature of my invention will e useful in many forms of magneticseparators, the idea bemg in. eneral to provide auxiliarymagnetzingmoifs so. wound and located as. to prevent the unduedispersion of the magnetic flux and to. concentrate such flux at thepart cular point where extreme density is re qpired for efiectiive,magnetic separation.v In Big. 3 I have illustrated b means of curves thevariation in the distri ution of magnetsm which may be produced by suchauxiliary counter-magnetizing coils. The curve H represents the magneticdensity at the surface of the revolving armature, the density beingtaken at the intersection of a horizontal plane through the center ofthe armaturathe surface L bei developed into a straight line for thesake 0 sim licity. The actual form of the surface is in, 'cated in thedotted lines. The intensity of the magnetic iield at the surface isindicated in the diagram by the dis tance to the right from the surfaceline L.

Without the counter-magnetizing coils A A the density ofthe flux-wouldbe indicated in a general way by the curve H, and if we consider thatthe minimum density required for separation is represented by thedistance of the line K K from the line L it will be seen that theeXtent' of surface having the required density is com aratively limited,being indicated by the istance X X upon the line K K. By the addition ofthe compensating windings A, as indicated in Figs. 1, 2, and

4, the magnetic flux at the ridges M M of the armature-surface moreremote from the central ridge is decreased, While the flux from thatportion of the surfacenearest the central ridge is considerablyincreased. The result is not only a much higher density at the extremeedge of the circumferential. ridge, but also a larger area of thesurface represented by the distance Y Y upon the line K K is permeatedwith a flux of the minimum separating strength. In other words, theamount of surface of the armature having a magnetic strength sullicientfor an effective separation is increased, so that the capacity of themachine is increased.

Referring to Figs. 5, 6, and 7, the theory upon, which the pole-pieceand armature are formed to secure the required concentration oi} themagnetic field will be apparent. The force of adhesion is a, function ofthe magnetic density. In the case of feebly magnetic substances it isnecessary to have a very high magnetic density in order to get anyconsideraiile degree of attractive force. The simplest means ofobtaining a very high magnetic density is by means of two pole-pieces ofa general conical, form, as indicated in Fig. 5. In order to use suchmagnetic densities in a continuously-acting commercial ore separator, Ihave made one ol the suriaccsin the form of a revolving wheel or drum B,a cross-section of which at the periphery would be wedge-shaped. II. theconi 'al form for the magnetic pole which opposes the revolving Wedge Bis retained, as shown in Figs. 6 and 7, it will be seen that the linesof force diverge from the stationary pole that is to say, the densitywill, be higher at the surface of the stationary polo than it will be atthe surface of the moving pole. This is undesirable, since it isintended that the magnetic particles should be attracted, but toward thestationary pole, not toward the revolving pole, so that the attractedmaterial may be readily removed. in the form shown in Figs. {5 and, 7the density will not he as high on the surface of the armature as it ison the conical point, partly on account of the spreading of the lines offorce toward the circuml'crcutial ridge of the armature and mrtlybecause the magnetic reluctance ol' 1 1c air-gap is decreased, therebyincreasing the saturation of the pole-yucca) N, which was alreadywm'liing at a very high magnetic density. i therefore prefer to make thepole-piece N in the form of a wedge, with its edge at right angles tothe wedge-sha ed surface ,of the armature, as shown in igs. 1 and 2. Thebody of the pole-piece is thus reinforced, thereby decreasing thesaturation, so as to partially com ensate for the extra saturation atthe wor 'ng point.

The armature is preferably laminated, so as to avoid eddy-currents andpermit the ar-,. mature to be turned in the intense magnetic field withthe minimum expenditure of ener y;

lhe location of the armature between two opposing pole-pieces ofopposite polarity, as shown, not only tends to approximatelybalance'"the"inagnetic pull upon the armature, but also insures theestablishment of a neutral point upon the surface of the armaturebetween the two poles, at which point even the more strongly-attractedmaterial will be released.

The operation of the machine will be apparent from the foregoingdescription of its structure. The material to be concentrated is fedinto the feed-chute D and the armature is rotated in the direction ofthe arrow, the field-magnet being energized by electric current throughthe magnetizing-coils. As the armature rotates the more ermeableparticles of ore will be attracted to its surface, the magnetic fluxfrom the pole-piece N becoming denser as the surface of the armature isapproached, and the pole-piece N being further shielded by thenon-magnetic plate E the more permeable particles adhering to thearmature are carried around in the rotation thereof past thedivider-plate F and are discharged on one side of said divider-plate,

while the non-magnetic particles continuing their course are dischargedon the other side of the divider-plate G. a

It will be apparent that my inventionis capable of modification, and Ido not'desire" to be understood as limiting myself in all re-' spects tothe precise construction shown in the drawings; but 7 I claim 1. In amagnetic separator, the combinationwith a revolving magnet tapered fromapproximately its axial center to its periphcry to form a wedge, of amagnet-pole taperingat its end, with the edge thereof in proximity tothe edge of said revolving magnet and at an angle thereto, and means forfeeding material to be separated into the gap between the edges of saidopposed magnets. 2. In a magnetic separator, a revolving magnetcomprising a shaft and a plurality of disks mounted thereon, said disksbeing of gradually-decreasing circumferences on each side of thelongitudinal center of the magnet, thereby forming a magnetic wedge, awe'dgev shaped magnet-pole with its edge in proxe iinity to the edge ofsaid revolving magnet and at .an angle thereto, and means forfeedingmaterial to be separated into the gap between the edges of saidmagnets.

3. In a magnetic separator, the combination with opposing pole-pieces ofopposite polarity, of an armature mounted to rotate between saidpole-pieces and tapered from approximately its axial center to itsperiphery to form a wedge, said armature being transversely .laminated,one of said polepieces being tapered in a general wedge shape, with itsedge at an angle to the edge of the armature-wedge, and means forfeeding material to be separated into the gap between saidlast-mentioned pole and said armature.

4. In a magnetic separator, the combination with a revolving laminatedcarrier tapered from approximately its axial center to form a workingsurface of wedge-shaped cross-section, of magnet pole-pieces of oppositepolarity disposed on opposite sides of said carrier, one of saidpole-pieces being constructed in a wedge shape, with its edge crossingthe wedge-shaped surface of said carrier approximately at right anglesthereto, and means for feeding material to be separated into the gapbetween the edges of said opposed magnets.

5. In a magnetic separator, the combination with opposing magneticsurfaces forming a working magnetic gap, of main magnetizing-coils forestablishing the magnetic flux, and auxiliary counter magnetizing coilsadapted to provide a magnetomotive force in opposition totheleakage-field, whereby the flux is concentrated in the working gap,substantially as set forth.

6. In amagnetic separator, the combination with a revolving magneticcarrier and a magnet pole-piece adjacent thereto forming a workinmagnetic gap, of magnetizing-coils for estab ishing a flux through saidgap, and auxiliary magnetizing-coils at the sides of said gapestablishing a magnetomotive force in opposition to the leakage-field atthe sides of said gap, whereby the flux is concentrated and directedacross said working gap, substantially as set forth.

7. In a magnetic separator, the combination with a revolving laminatedarmature havinga working surface of wedge-shaped cross-section, ofmagnet-poles of opposite polarity facing said armature, magnetizingcoilsfor establishing a flux between said poles and said armature, auxiliarycounter-magnetizing coils near the end of one of said polepieces at thesides thereof, said last-mentioned pole-piece being of wedge shape withits edge substantially at right angles to the plane of the wedge-shapedarmature, and means for passing material to be separatedinto contactwith said armature, and through the gap between said armaturc and saidlastnnentioned pole-piece, substantially as set forth.

8. In a magnetic separator, thecombina- In witness whereof- I hereuntovsubscribe tion with kopposing magnetic surfacesform- I my name-this 13thday of'March, A. D. 1905. ing a wor ing magnetica of m-ma netizing-coilat one side of said ggp. adapted to op- HENRY W I 5 'pose theleakage-field and to direct theflux Witnesses:

across said working gap, substantially as set IRVING MACDONALD, forth.DE WITT O. TANNER.

